Micropatterns on surfaces are processed into three-dimensional structures in the technical fields of, e.g., hard disk media, antireflection films, catalysts, microchips, and optical devices.
As the recording densities of magnetic recording apparatuses increase, patterned medium such as BPM (Bit Patterned Media) have been proposed as magnetic recording media for achieving high recording densities. A patterned medium can be obtained by processing the surface of a recording layer of a hard disk medium into a three-dimensional microstructure. Several methods can be used to process the surface into a three-dimensional microstructure. Examples are drawing methods using an electron beam and UV light, and a method using a self-organization phenomenon of a polymer or the like.
For example, a patterned medium manufactured by using a self-organizing process is expected to have “domains” in which magnetic dots are closely arranged. The domains have various sizes from a few ten nm to a few hundred μm. Regardless of the domain size, however, disturbance occurs in a dot array in a domain boundary. This disturbance of the array reduces a partial magnetic volume, and presumably causes noise when reading a magnetic signal by a head.